Fluid trap



Feb. 26 1929..

A. L. PENNIMAN, JR

Patented Feb. 26,' 1929.

UNITED STATES ABBOTT L. IENNIEAN, JR., OF BALTIMORE, MARYLAND.

FLUID TRAP.

Application tiled Iarch 9, 1925. Serial No. 14,012.

This invention pertains to fluid traps and more particularly to traps for automatically maintaining a substantially constant liquid level in a vessel by controlling the drainage of liquid from the vessel or alternatively by controlling the admission of liquid thereto. Among the many possible applications of the improved trap as a liquid supplycontroller may be mentioned its employment to control the admission of make-up water to condensers, evaporaters, surge tanks, etc. or the admission of oil or other fluid to a still or supply tank, while as a drainage controller'it may be employed to prevent water or other fluid from being drawn off into a priming pump or evaporating apparatus or to remove condensation water from bleeder heating apparatus. Many other applications of the device will doubtless occur to those skilledV in engineerin practice; but for purposes if illustrationt e invention is hereinafter more fully described as applied to the last named use, that is to say, to bleeder heating apparatus.

In modern steam turbine practice steam for` feed water heating is now commonly bled from several of the turbine stages, including stages working both at super-atmospheric and sub-atmospheric pressures, the cold su ply water first circulating through pipe co1 s surrounded by steam from the sure turbine stage and then successively circulating through other pipe coils surrounded by steam at higher pressures and temperatures coming from the higher turbine stages.

Each of such pipe coils is enclosedin a casing to which the bleeder steam from the turbine is admitted and as the steam condenses therein it is necessary to provide an outlet through which this water may drain from the heater casing, such outlet being provlded with an automaticall operating trap to prevent waste of uncon ensed steam.

For proper and economical operation at the vacuum 'or sub-atmosphericv stage or stages of the turbine, it is vitally important to prevent leakage of airv into any part of the system inclu ing the water heater casing and auxiliary parts, such for example as the trap. Automatic water traps of usual type are not adapted to prevent air leakage and in many cases are so sluggish due to ex.

cessive friction between moving parts, for example that occasloned when a part reciprocates through astuiling box, that they faill to maintain the water level with'any accuracy, thus wasting steam by failure to close the drain quickly or reducing the economy of heat transfer in the heater by allowing the water level to rise unduly.

The principal object of the present invention is to provide a trap capable of operating substantially as well at sub-atmospheric pressure as at high pressure,- which will not leak pressure either into or out from the system, and which will respond rapidly and with certainty to variations in water level.

In the accompanyin drawings, Fig. 1 is a dlagrammatic view i lustrating one application of the improved trap; Fig. 2 is a vertical section to large scale lllustrating the improved trap in detail;

' Fig. 3 is a section substantially on the line 3-3 of Fig. 2; and

Fig. 4 is a section similar to Fig. 1 but to small scale illustrating the tra as positioned to control admission of uid rather than its delivery.

i et at 4.

A supply pipe 5 enters the upper part of the casing, coming from any suitable source of steam or other heated'vapor, for example from the low pressure sta e of a steam turbine. A drain pipe 6 le s from the lower part of the casing of the heater for conducts ing away the water of condensation as it accumulates in the casing. This drain pi e 6 leads to the automatic trap forming the immediate subject matter of the resent invention, such trap being arrange to maintam a constant ow level of water in the. heaterl casing so as to avoid waste of steam or thev undue rise of water of condensation about thev pipe coils 2.

Thel improved trap shown in detail in Figs. 2 and 3 comprises a valve .housing 7 having an inlet chamber 8 which communicates with the drain pipe 6 and an outlet chamber 9 which communicates with a discharge pipe 10 leadingto any desired point.

The'inlet and outlet chambers .of the valve housing are se aratedl by a partition or septum '11 of substantially U-shape com risivligl the s aced parallel walls `12 an' 13.

ileas erein shown a U-shaped wall or partition is employed, `it is contemplated 'employing the U-shaped wall being to permit of the use of a balanced valve.

. lThe walls 12 and 13 are furnished with r aligned valve' orifices with which a balanced piston valve 14 cooperates. Normally this valve prevents the flow of fluid from the chamber 8 to the chamber 9 but when lifted allows such flow to take place.

The valve orifice in the wall 12 opens into a valve chamber 15 directly above the valve, such chamber in turn communicating with the inlet chamber 8. The space 16 below the valve also communicates with the inlet chamber 8 and with a passage in a pipe elbow 17 which leads to a valve casing 18. This valve casin 18 is furnished with a valve controlled'l by a hand .wheel 19, such valve normally being closed but when opened permitting the lfree flow of fluid from the chamber 8 out through the elbow 17 and through the valye casing 18 into a discharge pipe 20. This arrangement permits blowing out dirt from the heater 1 and valve housing 7, but does not constitute an essential feature of the invention.

The trap also comprises a casing or vessel 21 pre erably of cylindricalshape coniprisinga cylindrical shell closed at its opposite ends by means of covers 22 and 23 respectively, such covers preferably being removable. A pipe 24 connects the upper part of the vvessel 21 with the upper part of the heater 1 to equalize the pressure in the heater and in the vessel 21.

The casing 21 is furnished with a laterally 'projecting tubular `neck 25 terminating in a radial flange 26 by means of which it is attached to the valve housing 7. The neck 25 furnishes a free and unobstructed passage 27 communicating with the valve chamber 15 and axially aligned with the valve orifices in the walls 12 and 13.-

Brackets 28 and 29 project inwardly from the cover 22 of the vessel 21 and form supports' for a pin 30 constituting a ulcrum for a lever 31. This lever is arranged to swing in a vertical plane and supports a hollow loat 32 having a stem 35 forming a continuation of the lever 31. Y

The casing 21 `is preferably furnished with one nwmore baille plates or partitions, 33 to prevent fluid from surging longitudinally of the casing. The upper part of the partition 33 is furnished with a verticalk slot 34 forming a guide for the stem 35 of the float. The lower end of the slot 34 constitutes a stop vfor limiting downward movement of the lever 31, 4while a stop 36 secured to the wall of the casing limits upward movement of the lever. l

The lever is Apreferably/lfurnished with a slot for the reception of the up er end of a link 38 rpivotally connected to t e lever .neck`25 and its lower en 31 by means of a pin 39. This link e'xtends down through the assage 27 in the d is connected by means of a 'pivot pin 40 to the valve 14.

The operation of the device thus described is substantially as ollowsz-Steam being admitted through the ipe 5 to the heater 1 circulates about the plpe coils 2 and as its heat is transferred to the water ilowin through such coils the steamis condensed and tends to accumulate in. the lower part of the heater casing.- Normally the valve 14 is closed and the float 32 is in the full line position indicated in Fig. 2. As the any substantial resistance to movement of the valvesince the link 38 does not contact frictionally or otherwise with any ixedpart of the structure. Further, the valve 1s of balanced type, and these features thus com-` bined make the valve extremely sensitive to variations in water level in the casing 21 so that fluctuation in water level in the heater casing is reduced to a minimum.

Since the mechanism for actuating the valve 14 is yentirely enclosed in' the sub,- stantially air-tight casing 21 it is impossible for air to leak into the latter and there is -no interference with proper maintenance of vacuum` in the apparatus from which the supply pipe 5 may lead. The device is thus particularly useful in systems -wherein a sub-atmospheric pressure is maintained.

Under some circumstances it may be desired temporarily to hold the valve 14 open and for this purpose a spindle 41 having screw threaded engagement with a gland 42 carried by the member 17 is provided, such spindle being axially aligned with the valve and projecting up toward the bottom of the latter. By advancing this s indle the y valve may be opened regardless o the position of the ioat 32.y 'i In Fig. 4 a slightly modified arrangement of the valve 14 is illustrated, the valve proper in this case being inverted as respects its position in Fig. 2. With this arrangement the valve is o en when' the float is down, but is closed w en the iloat rises, thus adapting the device to the control'of the admission of Huid to a tank or vessel. While I have shown a preferred embodiment of the invention by way `vof example I wish it to be understood that the invention is not necessarily confined to thev specific arrangement of Aparts herein shown and described but that various modifications both in proportions and arrangements of parts may be made without departing from the spirit of the invention.

I claim: y

1. A. fluid trap comprising an air-ti ht vessel, a float. within said vessel, a va ve housing secured to the vessel, an o ening from the vessel into the housing, sai housing having inlet and outlet passages, the inlet passage communicating with said o ening, and a valve controlling the flow of uid from the inlet passage, link means opera tively connecting the float and `valve and passing freely through the opening therebetween to the outlet passage, said valve housing having a normally closed clean out passage leading from a point substantially in axial ali nment with the valve.

2. A uid trap comprising an air-tight vessel, a float within said vessel, a .valve housing seeured'to the vessel, an opening" from the vessel into the housing said housi-ng having inlet and outlet passa es, the inlet passage communicating with said o ening, a valve controlling the flow of uid from ,the inlet passage to the outlet `pas-I sage, link means operatively connecting the float and valve and passing freely through the opening therebetween, said valve housing havin la blowoi passage leading from a point su stantially in axial alignment with the valve and leading from the inlet side of the valve, and a normally closed valve controlling said passage.

3. A fluid trap comprising a closed ves- .sel having an orifice in its under wall, a float within said vessel, means constraining the iioat to move in a substantially vertical plane, a valve housing secured to the wall of lthe vessel, said housing having an opening in its wall axiall ali ned with the orice in theunder wal of t e vessel, a U-shaped septum separating the inlet end :from the l outlet end of the valve housin said septum having ali ed valve orifices 1n its parallel walls, sai orifices bein axially aligned with the orifice in the wa l of said vessel, a valve of balanced tlyfpe'controlling the passage of fluid throug said valve orifices, and a pivoted link passing freely through the opening between the float chamber and valve c amber verticall connecting' said valve with the loat, an a blow-off passa-ge leading from the valve chamber in axial alignment with said opening and said valve orifices. i p

Signed by me at Baltimore, Maryland, this 27th day offFebruar 1925.

ABBOTTKL. P NNIMAN, JR. 

